/*
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

#include "FontAtlasGeneratorBase.hpp"
#include "Base/Logger.hpp"
#include <zlib.h>
#include <filesystem>
#include <fstream>
#define STBI_MSC_SECURE_CRT
#define STB_IMAGE_WRITE_IMPLEMENTATION
#define STBIW_ZLIB_COMPRESS OpenVulkano::Utils::STBZlibCompressor
#include <stb_image_write.h>

namespace OpenVulkano::Scene
{
	std::pair<FtLibraryRecPtr, FtFaceRecPtr> 
		FontAtlasGeneratorBase::InitFreetype(const std::variant<std::string, Array<char>>& source)
	{
		FT_Library library;
		auto error = FT_Init_FreeType(&library);
		if (error)
		{
			throw std::runtime_error(fmt::format("Could not initalize freetype library. {}", GetFreetypeErrorDescription(error)));
		}
		FT_Face face;
		if (std::holds_alternative<std::string>(source))
		{
			error = FT_New_Face(library, std::get<0>(source).c_str(), 0, &face);
		}
		else
		{
			auto& arr = std::get<1>(source);
			error = FT_New_Memory_Face(library, (const FT_Byte*) (arr.Data()), arr.Size(), 0, &face);
		}
		if (error == FT_Err_Unknown_File_Format)
		{
			throw std::runtime_error("Unknown font file format\n");
		}
		else if (error)
		{
			throw std::runtime_error(fmt::format("Font file could not be opened or read or it's corrupted. {}", GetFreetypeErrorDescription(error)));
		}

		// some fancy font without unicode charmap
		if (face->charmap == nullptr)
		{
			throw std::runtime_error("Selected font doesn't contain unicode charmap");
		}
		return { FtLibraryRecPtr(library), FtFaceRecPtr(face) };
	}

	std::string FontAtlasGeneratorBase::GetFreetypeErrorDescription(FT_Error error)
	{
		if (const char* s = FT_Error_String(error))
		{
			return s;
		}
		return fmt::format("Error code is {}", error);
	}

	void FontAtlasGeneratorBase::SaveAtlasMetadataInfo(const std::string& outputFile, bool packIntoSingleFile) const
	{
		if (m_atlasData->glyphs.empty())
		{
			Logger::DATA->info("No glyphs loaded. Nothing to save.");
			return;
		}
		std::string fileName = outputFile;
		uint32_t packedFlag = packIntoSingleFile;
		if (packIntoSingleFile)
		{
			std::filesystem::path fPath(fileName);
			fileName = (fPath.parent_path() / fPath.stem()).string() + "_packed.png";
			SavePng(fileName);
		}
		std::fstream fs(fileName.c_str(), std::ios_base::out | std::ios_base::binary | (packedFlag ? std::ios_base::app : std::ios_base::trunc));
		fs.write(reinterpret_cast<const char*>(&m_atlasData->meta), sizeof(AtlasMetadata));
		uint64_t metadataBytes = sizeof(AtlasMetadata);
		for (const auto& [key, val] : m_atlasData->glyphs)
		{
			fs.write(reinterpret_cast<const char*>(&key), sizeof(uint32_t));
			fs.write(reinterpret_cast<const char*>(&val), sizeof(GlyphInfo));
			metadataBytes += sizeof(uint32_t);
			metadataBytes += sizeof(GlyphInfo);
		}
		fs.write(reinterpret_cast<const char*>(&metadataBytes), sizeof(uint64_t));
		fs.write(reinterpret_cast<const char*>(&packedFlag), sizeof(uint32_t));
		fs.close();
	}

	void FontAtlasGeneratorBase::SavePng(std::string output) const
	{
		stbi_flip_vertically_on_write(1);
		if (std::filesystem::path(output).extension() != ".png")
		{
			output += ".png";
		}
		stbi_write_png(output.c_str(), m_atlasData->img->resolution.x, m_atlasData->img->resolution.y, m_channelsCount,
		               m_atlasData->img->data.Data(), m_channelsCount * m_atlasData->img->resolution.x);
	}

	void FontAtlasGeneratorBase::SetupAtlasData(Math::Vector2ui textureResolution, double lineHeight,
	                                            FontAtlasType::Type atlasType)
	{
		// generate texture
		m_atlasData->img = std::make_unique<Image::Image>();
		m_atlasData->img->resolution = Math::Vector3ui(textureResolution, 1);
		m_atlasData->img->dataFormat = m_channelsCount == 1 ? DataFormat::R8_UNORM : DataFormat::R8G8B8A8_UNORM;
		m_atlasData->img->data = Array<uint8_t>(m_atlasData->img->dataFormat.CalculatedSize(textureResolution.x, textureResolution.y));
		m_atlasData->texture.resolution = m_atlasData->img->resolution;
		m_atlasData->texture.textureBuffer = m_atlasData->img->data.Data();
		m_atlasData->texture.format = m_atlasData->img->dataFormat;
		m_atlasData->texture.size = m_atlasData->img->data.Size();
		m_atlasData->meta.atlasType = atlasType;
		m_atlasData->meta.lineHeight = lineHeight;
		if (atlasType == FontAtlasType::BITMAP)
		{
			m_atlasData->texture.m_samplerConfig = &SamplerConfig::NEAREST;
		}
	}

	void FontAtlasGeneratorBase::SetGlyphData(GlyphInfo& info, Math::Vector2d bearing, Math::Vector2d size,
	                                          const Math::AABB& aabb, double advance)
	{
		const double bearingX = bearing.x;
		const double bearingY = bearing.y;
		const double w = size.x;
		const double h = size.y;
		const double l = aabb.min.x;
		const double r = aabb.max.x;
		const double t = aabb.max.y;
		const double b = aabb.min.y;

		info.xyz[0].x = bearingX;
		info.xyz[0].y = h - bearingY;
		info.uv[0].x = l / m_atlasData->texture.resolution.x;
		info.uv[0].y = b / m_atlasData->texture.resolution.y;

		info.xyz[1].x = bearingX + w;
		info.xyz[1].y = h - bearingY;
		info.uv[1].x = r / m_atlasData->texture.resolution.x;
		info.uv[1].y = b / m_atlasData->texture.resolution.y;

		info.xyz[2].x = bearingX + w;
		info.xyz[2].y = bearingY; //h - bearingY + h;
		info.uv[2].x = r / m_atlasData->texture.resolution.x;
		info.uv[2].y = t / m_atlasData->texture.resolution.y;

		info.xyz[3].x = bearingX;
		info.xyz[3].y = bearingY;
		info.uv[3].x = l / m_atlasData->texture.resolution.x;
		info.uv[3].y = t / m_atlasData->texture.resolution.y;

		info.advance = advance;
	}

	std::set<uint32_t> FontAtlasGeneratorBase::LoadAllGlyphs(const std::variant<std::string, Array<char>>& data)
	{
		const auto& [lib, face] = InitFreetype(data);
		std::set<uint32_t> s;
		FT_UInt glyphIndex;
		FT_ULong unicode = FT_Get_First_Char(face.get(), &glyphIndex);
		while (glyphIndex != 0)
		{
			s.insert(unicode);
			unicode = FT_Get_Next_Char(face.get(), unicode, &glyphIndex);
		}
		return s;
	}

}